[Dynamics of adaptation and maladaptation phenomena in rats exposed to weak chronic stimulation]

Experiments were carried out with rats to study the influence of disturbing artifical light-dark regimens. The findings are consistent with the definition of "relatively weak stress-stimuli" which, according to R. BAUMANN, can be essential in causing regulation diseases. Disturbances in the circadian patterns of spontaneous motor activity are described as an inversion of normal activity maxima and minima, as periodicity step-down and as a dissolution of the day-periodical order. Their occurrence is proportional to the magnitude of the disturbing effect. As vegetative disturbing effects there occurred transient hypertensive derangements, the extent of which is inversely proportional to the magnitude of the stressing stimulus. These differences are discussed basing on a hypothesis of differently synthetized cerebro-visceral regulation mechanisms.